F. G. H. PRICE ON BEDS STEAK FOLKESTONE. 431 



21. On the Beds between the Gault and Upper Chalk near Folkes- 

 tone. By F. G. Hilton Price, Esq., F.G.S. (Read March 7, 

 1877.) 



We have no better section of the Upper Cretaceous rocks than at 

 Lydden Spout, which is a name given to a portion of the cliff between 

 Folkestone and Dover. 



The chalk cliffs at this locality were carefully measured by Mr. C. 

 E. De Ranee, F.G.S. (of H.M. Geological Survej*), and myself; 

 and the height was found to be 433 feet above the mean sea- 

 level. The thickness of the beds between the Upper Gault and the 

 first bed of flints (Upper Chalk) is 348 feet. 



These beds I propose to divide into three general groups, i. e. 

 Chalk Marl, Grey Chalk, and Lower Chalk, the former two corre- 

 sponding with the Cenomanien of D'Orbigny, and the latter with his 

 Turonien. As these divisions contain several well-marked lithologi- 

 cal bands or beds, I have again subdivided them into six zones and 

 nine beds, distinguishable by their palseontological contents or litho- 

 logical characteristics. 



Mr. Whitaker, in vol. iv. p. 33 of the Geological- Survey Memoirs, 

 quoting Phillips, estimates the Grey Chalk or Chalk Marl at about 

 200 feet, and describes it as varying in colour and texture, but 

 softer, more sandy, and less compact than the other divisions. He 

 makes his division extend to the top of the thin yellowish bed, the 

 zone of Belemnites plenus. 



It will be seen from the present paper that I have given the 

 §ame limits for the Grey Chalk and Chalk Marl together as Mr. 

 Whitaker, and that I have estimated the thickness of those beds at 197 

 feet ; but instead of grouping them both together as Chalk Marl, I 

 have measured the Chalk Marl from the top of the Upper Gault, and 

 have carried it up to the top of the zone of Plocoscyphia matandrina, 

 in all about 24 feet thick. Here I consider the Grey Chalk 

 commences, extending to the top of the Belemnites-plenus band 

 (yellowish chalk), and having a thickness of 173 feet. The Lower 

 Chalk is 150 feet thick ; it is measured from the top of the Belem- 

 nites-plenns zone to the Upper Chalk (first line of flints). 



Mr. F. Drew has given a short note on this section in Whitaker's 

 ' Memoir ' of the Geological Survey, vol. iv. p. 33, in which he has 

 divided it into Chalk Marl, White Chalk without flints, and concre- 

 tionary (?) nodular chalk. He does not give the thickness of the Chalk 

 Marl. 



The " white chalk without flints," of Drew, is 138 feet thick, and 

 equals my bed vi. of the Grey Chalk, the zone of Holaster subglobosus, 

 which is 148 feet thick according to my calculations. 



The concretionary (?) nodular chalk, 73 feet thick, is capped 

 by chalk without flints and white chalk with few flints. 



The concretionary nodular chalk is equivalent to the beds above 

 the Belemnites-plenus zone, and is strangely near to Dr. Barrois's de- 



